mladenjovanovic/shorts: Estimate distance corrections

shorts 1.1.5

• Fixed wrong error message from the plot.shorts_fv_profile() function
• Minor model print aesthetic changes
• Fixed calculation of the residuals, which is now correctly calculated using observed - predicted. This calculation is implemented in the residuals() S3 method, as well as with internal function shorts_model_fit() that provides model fit estimates (i.e. RMSE, MAE, MAPE)
• Fixed calculation of the residuals in the vignette
• Added model_using_splits_with_distance_correction() function that implements novel model definition to estimate flying start distance
• Added mixed_model_using_splits_with_distance_correction() function that implements novel model definition to estimate flying start distance